Gaya APA

Nitrogen in the environment : source, problems and management / edited by J.L Hatfield, R.F Follett. (2008). : London : Elsevier.

Gaya MLA

Nitrogen in the environment : source, problems and management / edited by J.L Hatfield, R.F Follett. Ed. Ke- 2. : London : Elsevier, 2008. Text.